Article
Astronomy & Astrophysics
Sergey Khoperskov, Ivan Minchev, Noam Libeskind, Misha Haywood, Paola Di Matteo, Vasily Belokurov, Matthias Steinmetz, Facundo A. Gomez, Robert J. J. Grand, Yehuda Hoffman, Alexander Knebe, Jenny G. Sorce, Martin Spaare, Elmo Tempel, Mark Vogelsberger
Summary: This study analyzes six M31 and MW analogs from the HESTIA suite of cosmological hydrodynamical zoom-in simulations to explore the contribution of mergers to the formation of in situ stellar halos. The research reveals that mergers have a significant impact on the formation and dynamic features of stellar halos.
ASTRONOMY & ASTROPHYSICS
(2023)
Article
Astronomy & Astrophysics
Sergey Khoperskov, Ivan Minchev, Noam Libeskind, Misha Haywood, Paola Di Matteo, Vasily Belokurov, Matthias Steinmetz, Facundo A. Gomez, Robert J. J. Grand, Yehuda Hoffman, Alexander Knebe, Jenny G. Sorce, Martin Spaare, Elmo Tempel, Mark Vogelsberger
Summary: This study explores the phase-space structure of merged stars by analyzing six analogues of M31/MW, finding significant overlaps between merger remnants and in situ stars in different coordinate systems. Moreover, the positions of merger debris frequently change with time. An age gradient is observed in the L-z-E coordinate system, allowing for the use of stellar ages to determine the date of merger events. Accreted stars can be identified using root J(r) values, and different merger debris can be better distinguished from each other and in situ stars using the (J(z)/J(r)-orbital eccentricity) kinematic space.
ASTRONOMY & ASTROPHYSICS
(2023)
Article
Astronomy & Astrophysics
Sergey Khoperskov, Ivan Minchev, Noam Libeskind, Vasily Belokurov, Matthias Steinmetz, Facundo A. Gomez, Robert J. J. Grand, Yehuda Hoffman, Alexander Knebe, Jenny G. Sorce, Martin Spaare, Elmo Tempel, Mark Vogelsberger
Summary: This study explores the chemical abundances and kinematics of stellar populations in galaxies using simulations, revealing differences in elemental abundances between merger debris and survived dwarf galaxies. The accreted stellar haloes show gradients in metallicity and alpha-to-iron ratio, suggesting different formation locations. The measurements of halo stars in the inner Milky Way can provide valuable information about the parameters of the most massive merger in Gaia-Sausage-Enceladus. The metallicity distribution functions of individual debris show multiple peaks, and their abundances can be used to distinguish between different merger events.
ASTRONOMY & ASTROPHYSICS
(2023)
Article
Astronomy & Astrophysics
Claudia del P. Lagos, Eric Emsellem, Jesse van de Sande, Katherine E. Harborne, Luca Cortese, Thomas Davison, Caroline Foster, Ruby J. Wright
Summary: We use the eagle hydrodynamical simulations to study the impact of galaxy mergers on the formation of slow rotator galaxies, explore their intrinsic properties, and investigate the connection between quenching and kinematic transformation.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Gauri Sharma, Paolo Salucci, Glenn van de Ven
Summary: In this study, a pilot analysis of high redshift galaxy rotation curves is presented, which aims to constrain the structure of dark matter halos across cosmic time. Through mass modeling, it is found that dark matter halos have gradually expanded over the past 6.5 billion years. Comparisons with state-of-the-art galaxy simulations show that the dark matter cores of star-forming galaxies at z ~ 1 are smaller and denser than their local counterparts. This empirical evidence provides insights into the gravitational potential fluctuations in the inner region of galaxies and can be verified with deep surveys and future missions.
ASTRONOMY & ASTROPHYSICS
(2022)
Article
Astronomy & Astrophysics
Simon Deeley, Michael J. Drinkwater, Sarah M. Sweet, Kenji Bekki, Warrick J. Couch, Duncan A. Forbes
Summary: By combining observational and simulation data, it has been found that compact elliptical galaxies have two main formation pathways: stripping from a larger host galaxy and gradual buildup of stellar mass in isolated environments. The proportions are 32% and 68% respectively. The observed differences between isolated and host-associated compact elliptical galaxies can be fully explained by the dominance of different formation pathways in each environment.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
Simon Deeley, Michael J. Drinkwater, Sarah M. Sweet, Kenji Bekki, Warrick J. Couch, Duncan A. Forbes, Arianna Dolfi
Summary: The formation of S0 galaxies is complex, with two main pathways identified: gas stripping via group infalls and significant merger events. S0 galaxies formed through mergers feature a transient star-forming ring that matches observations.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
C. Murugeshan, V. A. Kilborn, B-Q For, O. Wong, J. Wang, T. Westmeier, A. R. H. Stevens, K. Spekkens, P. Kamphuis, L. Staveley-Smith, K. Lee-Waddell, D. Kleiner, B. S. Koribalski, M. E. Cluver, S-H Oh, J. Rhee, B. Catinella, T. N. Reynolds, H. Denes, A. Elagali
Summary: Using high-resolution ASKAP observations of galaxies in the Eridanus supergroup, we studied their HI, angular momentum, and star formation properties, finding consistency with previous works. Environmental processes, such as tidal interactions, were found to significantly impact the relationship between atomic gas fraction and integrated atomic disc stability parameter in Eridanus galaxies. The majority of Eridanus galaxies were also found to be HI deficient compared to normal star-forming galaxies in the field, with indications of suppression in star formation due to their environment.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
Ling Zhu, Glenn van de Ven, Ryan Leaman, Annalisa Pillepich, Lodovico Coccato, Yuchen Ding, Jesus Falcon-Barroso, Enrichetta Iodice, Ignacio Martin Navarro, Francesca Pinna, Enrico Maria Corsini, Dimitri A. Gadotti, Katja Fahrion, Mariya Lyubenova, Shude Mao, Richard McDermid, Adriano Poci, Marc Sarzi, Tim de Zeeuw
Summary: We report the discovery of ancient massive merger events in the early-type galaxies NGC 1380 and NGC 1427, and analyze their stellar orbits, age, and metallicity distributions. The formation of the hot inner stellar halo in both galaxies is found to require previous mergers with massive satellite galaxies, with estimated merger masses of about one-fifth and one-fourth of their current stellar masses for NGC 1380 and NGC 1427 respectively. The last major merger in NGC 1380 is the first one quantitatively inferred beyond the local volume, and it is the oldest and most massive merger uncovered in nearby galaxies so far.
ASTRONOMY & ASTROPHYSICS
(2022)
Article
Astronomy & Astrophysics
Jeremy Fensch, Frederic Bournaud
Summary: The gas mass fraction in high-redshift galaxies plays a crucial role in driving the evolution of giant clumps, with lower gas fractions leading to short-lived clumps and higher gas fractions resulting in long-lived clumps. This suggests that the gas fraction is the primary physical parameter determining the violent disc instabilities and evolution of giant clumps in high-redshift galaxies.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
C. Pulsoni, O. Gerhard, M. Arnaboldi, A. Pillepich, V. Rodriguez-Gomez, D. Nelson, L. Hernquist, V. Springel
Summary: The study reveals that the rotational support and intrinsic shapes of stellar halos in early-type galaxies are influenced by their accretion and merger histories, as well as the stellar mass. Low-mass galaxies are mainly driven by in-situ stars in shaping their halos, while high-mass galaxies and events with high f(exsitu) values affect the rotation velocity and shape.
ASTRONOMY & ASTROPHYSICS
(2021)
Article
Astronomy & Astrophysics
Adam B. Watts, Barbara Catinella, Luca Cortese, Chris Power, Sara L. Ellison
Summary: Observations of disturbances in the cold neutral atomic hydrogen (HI) in galaxies are common, but the reasons for these disturbances remain unclear. Studies using ALFALFA and xGASS surveys, as well as post-merger galaxies, show that the link between global HI asymmetry and the gas properties of galaxies is complex and needs further exploration.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
Caro Derkenne, Richard M. McDermid, Adriano Poci, J. Trevor Mendel, Francesco D'Eugenio, Seyoung Jeon, Rhea-Silvia Remus, Sabine Bellstedt, Andrew J. Battisti, Joss Bland-Hawthorn, Anna Ferre-Mateu, Caroline Foster, K. E. Harborne, Claudia D. P. Lagos, Yingjie Peng, Piyush Sharda, Gauri Sharma, Sarah Sweet, Kim-Vy H. Tran, Lucas M. Valenzuela, Sam Vaughan, Emily Wisnioski, Sukyoung K. Yi
Summary: We investigate the impact of environment on the internal mass distribution of galaxies using the MAGPI survey. We find that galaxies in high density clusters have less centrally concentrated mass distribution compared to galaxies in low-to-mid density environments. Our results suggest that environment plays a role in the internal mass distribution of galaxies, with no evolution of the slope in the last 3-4 Gyr.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
Yuren Zhou, Yanmei Chen, Yong Shi, Dmitry Bizyaev, Hong Guo, Min Bao, Haitong Xu, Xiaoling Yu, Joel R. Brownstein
Summary: In this study, we select 456 gas-star kinematically misaligned galaxies and analyze their properties in detail. We find that misaligned galaxies generally have lower gas detection rates and molecular gas mass fractions, as well as smaller sizes and higher Sersic indices. For misaligned galaxies in star-forming states, they tend to show more asymmetric gas velocity fields. As for misaligned quiescent galaxies, there are possibly three origins.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Haitong Xu, Yanmei Chen, Yong Shi, Yuren Zhou, Dmitry Bizyaev, Min Bao, Minje Beom, Jose G. Fernandez-Trincado, Xiao Cao
Summary: We investigated galaxies with kinematically misaligned gas and stellar components, and classified them into star-forming, green-valley, and quiescent galaxies. Our results show significant differences between misaligned galaxies and control samples in terms of gas and stellar motion ratios, central star formation activity, and gas-phase metallicity. These findings suggest that external gas accretion plays an important role in the evolution of galaxies, affecting both their dynamics and stellar populations.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)